Calckey has been one of the more popular Fediverse apps for a while now, and just of today they did a major rebranding.
Firefish’s official account is now live at @firefish. Official announcement post from 4 hours ago.
Currently infosec.town has fully migrated over to Firebird 1.0.0; calckey.social is still in the process of migrating.
As of this thread, the most up-to-date version is hosted on the Codeberg repository. A new docker will be supported at https://hub.docker.com/u/thatonecalculator/firebird once Kainoa finishes sorting out everything (hopefully).
It has a lot more features compared to Mastodon - I made the switch and am happy with it so far.